QL Block Versus EO Plane Block for Analgesia After Open Nephrectomy

The study is a prospective, randomized clinical trial designed to compare the analgesic efficacy of the transmuscular quadratus lumborum block with the external oblique plane block in adult patients undergoing open nephrectomy.

Open nephrectomy is associated with substantial postoperative pain because of the extent of the surgical incision, muscular dissection, and manipulation of retroperitoneal structures. Effective postoperative analgesia is important to facilitate recovery, mobilization, respiratory function, and patient comfort while minimizing opioid requirements.

The quadratus lumborum block is a posterior abdominal wall fascial plane block in which local anesthetic is deposited in relation to the quadratus lumborum muscle. The technique may provide analgesia over several thoracoabdominal dermatomes and may have both somatic and visceral analgesic effects. The external oblique plane block is a more superficial fascial plane technique that targets the lateral abdominal wall and may provide effective somatic analgesia.

Eligible patients will be randomly allocated in a 1:1 ratio to receive either a transmuscular QL block or an EO plane block before induction of general anesthesia. All patients will receive standardized general anesthesia and multimodal postoperative analgesia. The regional blocks will be performed under ultrasound guidance by an experienced anesthesiologist.

The primary outcome is total intravenous morphine consumption during the first 24 postoperative hours. Secondary outcomes include pain intensity at predefined postoperative time points, both at rest and with movement; time to first request for rescue analgesia; intraoperative and postoperative hemodynamic changes; recovery time; patient satisfaction; and adverse effects, including nausea, vomiting, respiratory depression, and complications related to the regional anesthesia technique.

The study will evaluate whether the QL block provides superior postoperative analgesia and opioid-sparing effects compared with the EO plane block following open nephrectomy.

**Inclusion Criteria:**

• Adult patients aged 18 to 65 years.
• Patients undergoing open nephrectomy at the National Cancer Institute, Cairo University.
• American Society of Anesthesiologists (ASA) physical status II-III.
• Body mass index (BMI) greater than 20 kg/m² and less than 35 kg/m².

**Exclusion Criteria:**

• Patient refusal to participate.
• ASA physical status IV.
• Age less than 18 years or greater than 65 years.
• BMI less than 20 kg/m² or greater than 35 kg/m².
• Known allergy or contraindication to any study medication, including local anesthetics or opioids.
• History of psychiatric disorders or chronic pain.
• Contraindications to regional anesthesia, including local infection at the injection site, pre-existing neuropathy, or coagulopathy.
• Severe organ dysfunction, including cardiac dysfunction (ejection fraction <40%), respiratory dysfunction (FEV1 <50% of predicted or requirement for home oxygen therapy), hepatic dysfunction (Child-Pugh class C), or renal dysfunction (estimated glomerular filtration rate <30 mL/min/1.73 m²).